Mark private methods of core libraries as invisible in the VM.

tests/language/reflect_core_vm_test.dart

Index: tests/language/reflect_core_vm_test.dart
===================================================================
--- tests/language/reflect_core_vm_test.dart	(revision 0)
+++ tests/language/reflect_core_vm_test.dart	(revision 0)
@@ -0,0 +1,20 @@
+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Test reflection of private functions in core classes.
+
+import "package:expect/expect.dart";
+import "dart:mirrors";
+
+main() {
+  var s = "string";
+  var im = reflect(s);
+  try {
+    im.invoke(const Symbol("_setAt"), [0, 65]);
+    Expect.isTrue(false);  // Unreachable.

[srdjan, 2013/08/23 13:58:18]

Expect.throws(() =>im.invoke(const Symbol("_setAt"), [0, 65]), (e) => e is
NoSuchMethodError);

+  } catch (e) {
+    Expect.equals(true, e is NoSuchMethodError);
+  }
+}
+